The crux of the issue remains NASA’s poor record on bringing spacecraft from the drawing board to the launch pad, the high costs of SLS, and the lack of funds to build anything but the rocket and spacecraft in the next decade.

All of which means that if this rocket and spacecraft somehow survive the next decade, even when it’s complete there won’t be anything built for astronauts to fly in beyond low-Earth orbit. Kraft and Moser are concerned because a big part of what Johnson Space Center does is build the kind of hardware — like moon buggies — that allow astronauts to explore wherever they’re going.

But if none of that stuff is being built, indeed if there’s no clear idea where astronauts are going to go, Johnson Space Center is in a bad spot.

There remains much frustration in the space community about the leadership of NASA continuing to downplay less expensive options to SLS. Most of these options use existing rockets — obviating the need for NASA to spend billions a year building its own version — to allow NASA to build stuff that could be launched on those rockets.

One of the most interesting options is fuel depots. NASA officials have talked down this technology’s potential, saying it’s not ready for prime time.

Dan Dumbacher, director of Engineering at the agency’s Washington headquarters, recently told me, “One of the things we learn more and more as we think through on-orbit propellant storage and transfer activities is there is a lot technology work that still has to be done to do that efficiently. Just getting the technology in hand is not a trivial matter.”

But an internal NASA study, revealed this week by Space Ref and completed last November, suggests these criticisms are unfounded, noting that depots “Should be a high priority for investment due to their potential to achieve Agency goals to achieve ‘Low Cost Reliable Access To Space.'”

With fuel depots the components needed for a mission beyond low-Earth orbit could be broken up into several launches, so NASA would not need to build a massive rocket upon which to launch fuel, a spacecraft and other components.